A Commerce City man was sentenced Thursday to 48 years in prison for the murder of his wife.

Derek Michael Johnston, 38, initially was charged with first-degree murder in the 2017 killing of 38-year-old Melissa Ehrmann. Johnston pleaded guilty to second-degree murder, which has a sentencing range of 35 to 48 years, according to the Adams County district attorney’s office.

On Sept. 6, police found Ehrmann badly beaten and unresponsive in the couple’s home at 14802 E. 119th Ave., according to a news release. The couple’s 19-month-old son was home at the time.

Ehrmann was taken to University of Colorado Hospital, where for more than four weeks she remained unresponsive with no brain function. She was taken off life support Oct. 6.

Johnston called police Sept. 6 saying that his wife had fallen down the stairs the night before and that he had helped her into bed only to awake 6:30 a.m. and find she was unconscious, the release said. Police found Ehrmann in bed, with ice packs around her body. She had been beaten from head to toe, prosecutors said.

Kieran Nicholson covers breaking news for The Denver Post. He started at the Post in 1986, at the old building on 15th and California streets. Nicholson has covered a variety of beats including suburbs, courts, crime and general assignment.

Prosecutors and investigators on Friday detailed the rising tensions between the two neighbors, a combative relationship that ended with the fatal shooting of the 46-year-old Cunningham, an assistant high school principal in Aurora and former University of Colorado football star.